The present invention relates to an ultrasonic diagnosis apparatus in which velocities of movement of an organ in motion of an object, such as a cardiac muscle of a heart and a blood vessel wall, are obtained and displayed and if necessary, on the basis of the velocities, other physical values representing conditions of the movement are calculated and displayed, and an image displaying system which can preferably used for the apparatus. Particularly, the ultrasonic diagnosis apparatus relates to an apparatus effective in diagnosis of ischemic cardiodiseases such as myocardial ischemia and angina pectoris, left ventricle distention disorders including hypertrophic cardiomyopathy, disorders of the conducting system of the heart like an Wolff-Parkinson-White syndrome.
Today, diagnosis of heart diseases tends to require quantitative estimation of functions of a cardiac muscle and blood vessel. Thus there are a wide variety of diagnostic methods for the quantitative estimation.
In a field of diagnosis by ultrasnonic beams, a real-time B-mode tomographic image is observed very often for the left ventricle of a heart, which is the key to evaluation of functions of the heart. In case that the above-mentioned ischemic cardiodiseases, left ventricle distention disorders, and disorders of a conducting system of the heart are considerably serious, the observation of the B-mode tomographic image is useful. But trouble is that it is practically impossible to acquire detailed information with respect to detection of local deteriorated portions in contraction ability in ischemic cardiodisease, objective diagnosis of left ventricle distention disorders, and detection of positions and extent of abnormal paries movement in a conducting system of the heart.
To overcome the drawback for ischemic cardiodisease, there is an exclusive analysis method of paries movement of a left ventricle. The analysis method is to measure changes in thickness of the cardiac muscle of the left ventricle in both its systole and diastole and to diagnose such that a portion of less changes in thickness is a deteriorated portion in contraction ability, or ischemia portion. Althrough there are various algorithms for the analysis method, they require tracing on a B-mode tomographic image an endocardium or epicardium of the left ventricle in both an end-systole and end-diastole.
A stress echography is also known for diagnosing myocardial ischemia. Carrying out the stress echography requires a heart to be stressed by exercise, drugs or an electric stimulus. And B-mode tomographic images of the heart will be recorded before and after stressing, respectively, to display those images on the same monitor. Then changes in thickess of the cardiac muscle are compared in its systole and diastole (normally, thicker in its systole), detecting a portion of myocardial infarction. It is also required for this detection to trace the inner and outer walls and the center line of a cardiac muscle on the images to get the contour of it.
The conventional tracing has been done by manual operation through a keyboard or track ball. This manual operation requires a deal of labor and takes a lot of time, thus being impossible to process in real time and being poor reproducibility.
Thus, there has been provided an automatic tracing method by which contour data of a cardiac muscle are automatically extracted from data of a B-mode tomographic image. The automatic trace uses differences in echo level between a cardiac muscle and its surrounding portion; a cardiac muscle is higher in echo level than its surrounding portion. A threshold level is set for an echo signal to detect the contour existing on the corresponding position to the threshold level.
However, in the above automatic trace, when an amplification factor (gain) for the echo signal is changed, the position extracted as a contour line is also moved. This results in that it is impossible for the B-mode image to automatically depict the contour of a cardiac muscle in real time and with high accuracy.
On top of the above difficulty, for the foregoing objective diagnosis of left ventricle distention disorders and detection of position and extent of abnormal paries movement in a conducting system of the heart, diagnosis methods have not yet been established that are simple and useful with an ultrasonic diagnosis apparatus.
Further, when conditions of a cardiac muscle and a blood vessel wall are observed, a conventionally used B-mode image is based on a real time display. Therefore, the image changes moment by moment and it is almost difficult to provide properly enough information over measurement time.